Manufacturing method of semiconductor photonic device substrate
View Patent ↗In a manufacturing method of a semiconductor photonic device substrate, before multi-layer films different in material composition are successively and gradually crystal-grown in one chamber, an inter-layer growth rate model showing a relation in growth rate between each layer is defined, a growth rate of a film corresponding to at least one or more layers is obtained by actual crystal growth using an individual substrate, a growth rate of a film corresponding to other layers is estimated from the obtained growth rate by the inter-layer growth rate model, and a growth time is determined in accordance with a film thickness of each layer of the semiconductor photonic device substrate based on the actually obtained growth rate and the estimated growth rate. These steps are carried out by using a computer system connected to an MOCVD equipment, and then, a crystal growth of the semiconductor photonic device substrate is performed.
1. A manufacturing method of a semiconductor photonic device substrate using an MOCVD equipment,
wherein, before multi-layer films different in material composition are successively and gradually crystal-grown in one chamber, a process comprising:
a first step of defining, by statistical analysis, an inter-layer growth rate model showing a relation in growth rate between each layer as a linear relation;
a second step of obtaining a growth rate of a film corresponding to at least one or more layers by actual crystal growth using an individual substrate;
a third step of directly calculating a growth rate of a film corresponding to other layers from the growth rate obtained in the second step by using the inter-layer growth rate model; and
a fourth step of calculating a growth time in accordance with a film thickness of each layer of the semiconductor photonic device substrate based on the growth rate actually obtained in the second step and the growth rate calculated in the third step is carried out by using a computer system connected to the MOCVD equipment, and through the process above a crystal growth of the semiconductor photonic device substrate is performed.
2. The manufacturing method of a semiconductor photonic device substrate according to claim 1 ,
wherein the inter-layer growth rate model defined in the first step is a model showing a relation between the growth rate of the film corresponding to at least one or more layers and the growth rate of the film corresponding to other layers as a proportional relation or a linear relation with an intercept.
3. The manufacturing method of a semiconductor photonic device substrate according to claim 1 ,
wherein the semiconductor photonic device substrate is made up of a buffer layer, a DBR layer, an n-clad layer, an active layer, a p-clad layer and a current diffusion layer which are crystal-grown on a base substrate, and
in each of the layers, at least one or more layers having different material compositions are stacked.
4. The manufacturing method of a semiconductor photonic device substrate according to claim 1 ,
wherein, in order to define the inter-layer growth rate model defined in the first step, a process comprising:
an eleventh step of setting one or more inter-layer growth rate model candidates in advance;
a twelfth step of obtaining a growth rate of each layer by actual crystal growth using an individual substrate;
a thirteenth step of searching, from a database, an actual result value of a growth rate of a film corresponding to each layer which is actually crystal-grown by using an individual substrate over a plurality of past periods;
a fourteenth step of calculating a coefficient of the inter-layer growth rate model set in the first step by using an actual result value in a part of a period from among the actual result values of the growth rates in a plurality of periods acquired in the second step and the third step;
a fifteenth step of estimating a growth rate of a film corresponding to a layer to be a target of estimation in an inter-layer growth rate model by using a growth rate actual result value in a period not used for the calculation of the coefficient in the fourteenth step, and then obtaining an estimation error from the actual result value; and
a sixteenth step of selecting an inter-layer growth rate model used for determining a growth time at an actual crystal growth of the semiconductor photonic device substrate from among the inter-layer growth rate model candidates based on an accuracy of the estimation error is performed to define the inter-layer growth rate model.
5. The manufacturing method of a semiconductor photonic device substrate according to claim 4 ,
wherein the coefficient of the inter-layer growth rate model is calculated by a multiple regression analysis by using a plurality of actual result values in the fourteenth step of calculating the coefficient of the inter-layer growth rate model.
6. The manufacturing method of a semiconductor photonic device substrate according to claim 4 ,
wherein the coefficient of the inter-layer growth rate model is calculated by a PLS regression analysis by using at least one or more actual result values in the fourteenth step of calculating the coefficient of the inter-layer growth rate model.
7. The manufacturing method of a semiconductor photonic device substrate according to claim 6 ,
wherein there are at least two or more growth rates of films to be an input of a model, and the coefficient of the inter-layer growth rate model is calculated by using at least one or more actual result values which are smaller in number than the number of inputs of the model in the fourteenth step of calculating the coefficient of the inter-layer growth rate model.